DEEP-SEA camera systems have shown that Australian commercial fisheries are having little impact on sea floor biodiversity around Heard Island and the McDonald Islands (HIMI).

The cameras, along with scientific sampling, revealed that more than 98 per cent of sensitive sea floor biodiversity in the fishery had remained in pristine condition after 16 years of commercial fishing.

The eight-year study, funded by the Fisheries Research and Development Corporation, was a joint project between the Australian Antarctic Division, the Australian Fisheries Management Authority and fishing industry partners Austral Fisheries and Australian Longline.

Australian Antarctic Division fisheries scientist Dirk Welsford said the project aimed to investigate the potential impacts and sustainability of trawling and longlining (“demersal fishing”) for Patagonian toothfish in the Australian Fishing Zone at HIMI, and to develop technologies that could be used by other fisheries to address similar issues.

A small crustacean called an amphipod, collected during the camera trials. Picture: AADSource: Supplied

“A key part of the research was the development of underwater still and video camera systems, which attached to demersal fishing gear to observe the impact of the gear on sensitive sea floor habitat,” Dr Welsford said.

Australian Longline managing director Les Scott said the robust automated camera systems allowed fishing vessels to see the habitat they were working in.

“The cameras were key to a reliable understanding of the extent and nature of fishing interactions during commercial fishing activities,” Mr Scott said.

The research found that the risk that fishing would cause significant impacts to sea floor biodiversity at HIMI was likely to be low over the medium term.

The study recommended that risk assessments for the fishery be updated regularly, to evaluate the likely performance of the current management approach in the long term.

The research also found that the majority of vulnerable organisms lived on the sea floor at depths less than 1200m.

This habitat overlapped with trawl fishing to depths of 1000m and, to a lesser extent, longline fishing, which can fish deeper than 1000m.

However, scientists estimate that only 0.7 per cent of the sea floor within the HIMI fishing zone had some interaction with fishing gear since the fishery’s inception in 1997.

The study estimated that the HIMI Marine Reserve, where fishing is not permitted, contains more than 40 per cent of the sea floor organisms considered vulnerable to demersal fishing in the region.

“A key element of the management strategy for mitigating the impact of demersal fishing is the extensive marine reserves established around HIMI and Macquarie Island,” Dr Welsford said.

“This work has directly led to the expansion of the HIMI Marine Reserve by 6200 square kilometres, to protect a range of distinct sea floor habitats and vulnerable species of conservation significance. The HIMI Marine Reserve now covers over 71,000 sq km – protecting an area the size of Ireland.”